This invention relates to jack bolt devices used to separate structures that may normally be bolted or fastened together to form assemblies. The new jacking plate may be used to reinforce a particular structure as for example an aluminum structure that may deform under the force applied when a jacking screw is used to separate physical structures.
Jack bolt assemblies and devices have been used for many years to aid in separating structures that are assembled and fastened together by fasteners such as attachment bolts and nuts. Generally, two structures such as two flanges as part of an assembly or more directly two structural elements may be fastened together by bolts and nuts or other fasteners. When it is desired to separate the two structural elements a jack bolt may be used by engaging the screw threads of the jack bolt with a threaded aperture in one assembly element and rotating the jack bolt to apply force against the other assembly element to thereby separate the two assemblies. In normal use the composition of the two assemblies may be such that the force of separation does not cause any deformation of the structure of the assemblies.
In some applications requiring the use of a jack bolt for separating assemblies, there may not be a surface against which the jack bolt may be engaged to force separation of assemblies. An example of use of an insertable plate to provide a structure for application of a jack bolt is disclosed in U.S. Pat. No. 4,015,324. In this instance the plate must be transported with the jack bolt and inserted to allow use of the jack bolt. The assembly of pipe flanges is not an integral structure that allows simple engagement and use of a jack bolt for separation of the pipes. The use of an insertable plate is not feasible where access to an assembly is inhibited as addressed by the instant invention.
Other examples of jack bolt applications may require use of a washer, as the jack bolt may be a more complex assembly for separating and/or fastening pipe flange assemblies. Such an application is disclosed in U.S. Pat. Nos. 4,540,199 and 4,671,324. In this instance the assembly is no longer a simple jack bolt, but has an extension element that includes a washer and a fastening nut. The disclosure even includes a bearing as an alternate to the washer. This complex assembly may be designed to accomplish several specific operations related to separating and joining pipes; however, it may not be applicable for use in simple applications requiring separation of structural elements.
As can be seen, there is a need for a simple, attachable reinforcement device for use with structural elements that may deform under the force of a jack bolt.
An improved jack bolt reinforcement device according to the present invention comprises a jacking plate, which may be fastened intermediate, a structural assembly and a fastening nut.
In one aspect of the present invention a jacking plate comprises a plate having a bolt aperture formed therein through which a fastening bolt may be inserted. There may also be a plurality of fastening apertures formed therein for attachment of the jacking plate intermediate a first structural element and a nut fastener. The bolt aperture may be sized to inhibit a jack bolt from passing through the bolt aperture.
In another aspect of the invention the jacking plate may be comprised of a material structure of hardened metal to inhibit deformation of a structural element or nut fastener under the separation force of the jack bolt. The hardened metal may be stainless steel.
In yet another aspect of the invention a jack bolt apparatus for separating structural assembly elements may comprise a jacking plate having a bolt aperture therein attached intermediate an inner structural element and a nut fastener. A threaded bushing may be attached to an outer structural element through which the jack bolt may be threaded. The bolt aperture may be sized to inhibit the jack bolt from passing through the bolt aperture.
In a further aspect of the invention a method for separating structural assembly elements comprises the steps of attaching a jacking plate intermediate a first structural element and a nut fastener wherein the jacking If plate having a bolt aperture for insertion of a fastening bolt and for inhibiting passage of a jack bolt. A bushing may be attached to a second structural element. The jack bolt may be threaded through the bushing to apply force against the jacking plate and force the separation of the structural elements.